They swam back to the boat after it capsized under the weight of the whale.

Lambinon said one of the men's cellphones was still working and they called the boat's owner for help.

"On arrival on-scene a search commenced for the boat in dark, moonless conditions, and using illuminating flares to aid in the search, the boat was found about one nautical mile off-shore with all three men clinging onto the hull," he said.

Myburgh had broken ribs and an injured arm and leg. He was taken to hospital in a serious, but stable condition.